| REP | <radiobiology, unit> A roentgen equivalent physical is a unit of absorbed radiation approximately equivalent to a roentgen, an international unit of x- or gamma-radiation. An obsolete unit of measurement; that quantity of ionizing radiation of any kind which, upon absorption by living tissue, produces an energy gain per gram of tissue equivalent to that produced by 1 roentgen of X-rays or gamma-rays. Acronym: rep See: rad. (05 Mar 2000) |
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| rep protein | <protein> A protein that triggers a plasmid's replication. An acronym for Repetitive Extragenic Palindromicprotein, this protein is an enzyme produced by a mutant strain of E. Coli that unwinds the DNA helix. (09 Oct 1997) |
| rep-silver | Money anciently paid by servile tenants to their lord, in lieu of the customary service of reaping his corn or grain. See: Reap. Source: Websters Dictionary (01 Mar 1998) |
| parallel track | <pharmacology> A system for distributing certain experimental drugs to people who are unable to participate in ongoing clinical trials. (09 Oct 1997) |
| double track sign | In paediatric radiology, a less common sign of congenital pyloric stenosis, when barium is caught between mucosal folds in the hypertrophied pylorus. (05 Mar 2000) |
| track | To follow the tracks or traces of; to pursue by following the marks of the feet; to trace; to trail; as, to track a deer in the snow. "It was often found impossible to track the robbers to their retreats among the hills and morasses." (Macaulay) 2. To draw along continuously, as a vessel, by a line, men or animals on shore being the motive power; to tow. Origin: tracked; tracking. 1. A mark left by something that has passed along; as, the track, or wake, of a ship; the track of a meteor; the track of a sled or a wheel. "The bright track of his fiery car." (Shak) 2. A mark or impression left by the foot, either of man or beast; trace; vestige; footprint. "Far from track of men." (Milton) 3. <zoology> The entire lower surface of the foot;-said of birds, ect. 4. A road; a beaten path. "Behold Torquatus the same track pursue." (Dryden) 5. Course; way; as, the track of a comet. 6. A path or course laid out for a race, for exercise, ect. 7. The permanent way; the rails. 8. [Perhaps a mistake for tract] A tract or area, as of land. "Small tracks of ground." Track scale, a railway scale. See Railway. Origin: OF.trac track of horses, mules, trace of animals; of Teutonic origin; cf.D.trek a drawing, trekken to draw, travel, march, MHG. Trechen, pret. Trach. Cf. Trick. Source: Websters Dictionary (01 Mar 1998) |
| track and field | Sports performed on a track, field, or arena and including running events and other competitions, such as the pole vault, shot put, etc. (12 Dec 1998) |